Seattle, WA – Seattle Sounders FC announced that the club has year contract.
Rosales is coming off a season that saw him set a club record with 13 assists in 26 appearances while also scoring five goals.
The 30-year-old was named the MLS Newcomer of the Year for his performance last season, which helped Seattle finish second in the Western Conference and claim a third successive U.S. Open Cup title.
"Mauro was a huge impact on our team last year," said Sounders FC head coach Sigi Schmid. "He played well and made others better with his service and use of the ball. We are pleased to have him back as a Sounder."
After spending the previous three years with River Plate of Argentina, Rosales signed with Seattle on March 18, and has also spent time with Ajax and Newell's Old Boys prior to his arrival in MLS.
He has also earned 10 caps for Argentina and won an Olympic gold medal with his country in 2004.